Arrangement comprising a cathoderay tube having means for deflecting the cathode-ray beam



w. x EI'AL 2,532,738 ARRANGEMENT COMPRISING A CATHODE-RAY TUBE HAVING MEANS FOR DEFLECTING THE CATHODE-RAY BEAM Filed Feb. 1'7, 1949 Dec. 5, 1950 IN V EN TORS WILLEM SIX JOHAN LODEWIJK H. JONKER BAY W W AGENT Patented Dec. 5, 1950 OFFICE ARRANGEMENT COlliPRISING A CATHODE- RAY TUBE HAVING MEANS FOR DEFLECT- ING THE 'CATHODE-RAY BEAM Willem Six and Johan Lodewijk Hendrik Junker, Eindhoven, Netherlands, assignors to Hartford National Bank and Trust Company, Hartford,

Conn, as trustee Application February 17, 1949, Serial No. 76,9 2 4 In the Netherlands March 20, 1948 2 Claims.

In the main patent application No. 799,874 a circuit is described which comprises a cathoderay tube having means for the deflection of the cathode-ray beam, in which at one or more positions of the cathode-ray tubecurrent distribution takes place between at least two collecting electrodes, the current flowing in at least one of the circuits connected to one of the electrodes acting upon the deflection of the cathode ray beam in such manner that the beam is detained in the position concerned. In this circuit the current strength in at least one circuit connected to an electrode taking part in the current distribution exhibits, as a function of the deflection of the beam, a number of maxima and minima, the values of which vary monotonously and in the same sense as a function of deflection.

In a circuit of this kind there is a need of means for moving the cathode-ray beam from one position into the other, for which the main patent application already provides a number of solutions which substantialy utilise the variation in voltage at the deflection plates or the variation in current of the deflection coils.

The present invention relates to a different solution of this problem and exhibits the characteristic that for moving the cathode-ray beam from one position into the other, the current strength of the cathode-ray beam is varied in such manner that the number of stable adjustments of the beam is reduced to two at the most, which variation in current strength is eliminated as soon as the variation in deflection of the oathode-ray beam brought about thereby is substantially equal to the deflection necessary for obtaining the position desired.

In order that the invention may be more clearly understood and readily carried into efiect, it will now be described more fully by reference to the accompanying drawing.

The cathode-ray tube shown in Fig. 1 comprises means known per se and here shown only diagrammatically, for generating a cathode-ray beam, a set of plates 2 for deflecting the beam, together with two collecting electrodes 3 and Q. The electrode 3 is realized in such manner that at least part of the beam on being deflected either strikes the electrode 3 or the electrode 4. For this purpose it may exhibit, for example, suitably chosen apertures.

The electrode 3 is connected through a conductor 5 to the positive terminal of a source of supply, the negative terminal of which is connected to the cathode of the cathode-raytube. Furthermore the positive terminal of the source 2 of supply is connected by way of a resistance 6 and a conductor 1 to the collecting electrode 4, that extremity of resistance 6 which is remote from the source of supply being connected to one of the deflection plates.

In a circuit of this kind the current is traversing a circuit 1 as a function of the deflection which is determined by the voltage difierence V between the deflection plates, exhibits a plurality of maxima and minima as shown by curve 8 in Fig. 2. With suitable choice of the apertures in the electrode 3, the values of both the maxima and minima decrease monotonously when the deflection voltage increases.

The voltage V set up at the deflection plates and derived from the resistance 6 is furthermore in 1inear relation to the current is. flowing through the resistance 6., which relation is shown by a resistance line 9 in Fig. 2. The resistance 6 is chosen to be such that the line 9 intersects the curve 8 at a number of points. It has been explained in the main application that the intersections li! up to 14 inclusive provide stable positions for the cathode-ray beam, the intersections between these points being labile. Assuming the cathode-ray beam to occupy a position which corresponds to the intersection 12 of the curve B and the straight line 9. This position corresponds to a deflecting voltage V1. Now, if the beam is desired to be moved to a position corresponding to the intersection H, which corresponds to a deflecting voltage Vz, this may be carried out with the circuit according to the invention in the following manner.

A positive voltage pulse, which may exhibit, for example, the shape shown at It, is supplied to a control electrode P5 of the cathode-ray tube I. This results in an increase in current strength of the cathode-ray beam, so that the current flowing in the output circuit 1 will also increase, this higher current strength corresponding to a characteristic curve of the shape shown at l! in Fig. 2. Most of the intersections ID to M inclusive which were initially present are thus eliminated except the left-hand intersection which is only displaced and, as the case may be, the intersection located at the maximum deflection voltage. The increase in current also results in an increase in voltage loss across the resistance 6, so that the total active deflecting voltage is reduced and the beam will move to the left-hand side. The duration of the pulse It must be chosen to be such that the increase in current approximately ceases at the moment at which the beam has moved to the left through a distance which approximately justment at this stable point. beam occupies a position correspondingto a defiection voltage smaller than Vs. (which voltage corresponds to the labile intersection It) there will already be a tendency tomove to thezstable point H. It is preferable, however, to ensure that the duration of the pulse is chosen to be such that the deflection of the extremity of the pulse corresponds to a voltage comprised between V4 and V5, corresponding to the two'extremes of curve 8 on each side of the desired stable adjustment, H.

If a variation inpositionin the: othersense is desired, hence, for example, from point 12 to point- [3, this maybe ensured bysupplyingto a control electrode [5 a negative pulse of a value such that most of the stable adjustments disappear, whereupon the beam will move to the right-hand side and' may again be collected in the vicinity of the desired adjustment due to the pulse being discontinued.

What we claim is:

1. An electrical circuit arrangement, comprising an electron discharge tube having in the order named a source of an electron beam, of given electron density, deflecting means adapted to shift the position ofsaid'beam, a first collecting electrode and a second collecting electrode, an output circuit 7 comprising an impedance element coupled to said second, collecting electrode, means to derive a control'voltage from said" im- 4 l pedance element and to apply said control voltage to said deflecting means thereby to cause said beam to impinge on said first and second collectingelectrodes, and means tovar-y the current; distribution between said first. and second collecting electrodes comprising means to apply a signal voltage pulse to said source thereby to vary the electron density of said beam for a time 7 interval equal to the duration of said pulse.

2. An. electrical. circuit arrangement, comprising an electron discharge tube having in the order namedi asource of an electron beam of given electron density, a pair of deflecting electrodes adapted to shift the position of said beam, a first collecting electrode and a second collecting, electrode, an output circuit comprising, aresistive element coupled to said second collecting electrode, means interconnecting said second collecting electrode and one of said defleeting electrodes to derive a control voltage from said resistive element and to apply said control voltage to said one deflecting electrode thereby to cause said beamto impinge on said firstand' second collecting electrodes, and means to vary the current distribution bet-ween said first and second collectingelectrodes comprising means toapply a signal voltage pulse to said source thereby to--vary' the electron density of said beam for a time interval equal to the-duration of'said pulse.

WILLEM SIX. JOHAN LODEWIJK HENDRIK JONKER.

REFERENCES CITED The following references are oi record in the Name Date Meacham June 21, 1949 Number 

